1. Field of the Invention
The present invention relates to an electrostimulation system, and an electrostimulation electrode assembly and a biological implantable electrode therefor. In particular, the present invention relates to an electrostimulation system which applies electrical stimulus to the nervous tissue, an electrostimulation electrode assembly which applies electrical stimulus to the nervous tissue, and a biological implantable electrode which is connected to an electrical stimulus generation device placed in a biological body to apply electrical stimulus to the biological tissue, such as muscles, nerves, or heart, which requires electrical stimulus.
2. Description of Related Art
In the related art, a stimulus generation device is known which applies electrical stimulus for treatment to the nervous tissue or the biological tissue (linear tissue), such as muscles. Examples of the stimulus generation device include a nervous stimulation device, a pain relief device, an epilepsy treatment device, a muscle stimulation device, and the like.
In the stimulus generation device, a conducting wire which transmits electrical stimulus is implanted in the biological body for use so as to bring the conducting wire into close contact with a stimulation target in the biological body.
In general, the conducting wire has at least one electrode portion which applies electrical stimulus to the biological tissue or detects electrical excitation in the biological tissue, an electrical connector which is used for electrical connection to the stimulus generation device, and a lead body which is provided between the electrode portion and the stimulus generation device and transmits electrical stimulus.
For example, Japanese Unexamined Patent Application, First Publication No. 2004-173790 describes an implanted heart treatment device which stimulates the heart when the heart produces bradycardia to increase the heart rate, stimulates the vagus nerve when the heart produces tachycardia or fibrillation to decrease the heart rate. In the heart treatment device, a heart stimulation electrode is arranged inside the myocardium or the atrium, and a nerve stimulation electrode is arranged to be wound around the vagus nerve in the cervical region.
Japanese Unexamined Patent Application, First Publication No. 2008-67978 describes a biological implantable electrode lead which includes an electrode support having at least one arm portion, in which an electrode is formed, the arm portion being loaded to be wound around the biological tissue, such as the cervical vagus nerve.
Heretofore, a device, such as a heart pacemaker, an implantable defibrillation device, a nervous stimulation device, or a deep brain stimulation device, is known which applies electrical stimulus for treatment to the biological tissue, which requires stimulation. The device includes an electrical stimulus generation device which has an internal power supply and an electrical circuit necessary for electrostimulation, an electrode which is loaded in the biological tissue, which requires stimulation, to apply electrical stimulus to the biological tissue, and a conducting wire which transmits electrical information from the stimulus generation device to the electrode.
Of these, the biological implantable electrode placed in the body includes at least one electrode which applies electrical stimulus to the biological tissue, such as the heart, nervous tissue, or muscles, or detects electrical excitation in the biological tissue; a conducting wire sheathing body which has an electrical conductor and a biocompatible insulating sheath connected to the electrode; a connector which electrically connects various electrical stimulus generation devices, such as a heart pacemaker, an implanted defibrillation device, a nervous stimulation device, and a deep brain simulation device, to the conducting wire sheathing body; and the like.
As the biological implantable electrode of the related art, electrodes are known which are described in Japanese Unexamined Patent Application, First Publication Nos. 2008-67978 and 2005-58456. Japanese Unexamined Patent Application, First Publication No. 2008-67978 describes an electrode assembly for nervous stimulation which is implantable into the biological body. In the electrode assembly, an electrode at the tip of a conducting wire sheathing body has an arm portion, and the arm portion is loaded to be wound around the nerve. In the biological implantable electrode described in Japanese Unexamined Patent Application, First Publication No. 2005-58456, a lubricating coated layer is provided in a portion of the surface of an insulating sheath.